We're planning on flying to vancouver in early May, 3 nights in Vancouver, then via rial to Jasper. 3 nights in Jasper then a scenic tour to Banff. 5 nights in Banff then home from Calgary. We're on a budget hence economy via rail rather than rocky mountaineer. We had also hoped to do a whale watching trip and a wildlife tour to see bears. Is this possible at this time of year? What can we expect the weather to be like? Also what else would be a must given we only have 12 nights in total?